1. Field of the Invention
This invention relates to disc recording and transcribing apparatus, in general, and more specifically, to apparatus for depression of the spindle during a disc change cycle and inhibiting motion of the spindle during phasing of a loaded disc.
2. Description of the Prior Art
Representative of the prior art is U.S. Pat. No. 3,789,160 entitled "Dictation Apparatus with Disc Loading, Feeding and Ejecting Feature," issued to J. D. Bruer, et al., Jan. 24, 1974, which discloses a disc dictation system featuring automatic loading, feeding and unloading operations wherein the spindle is depressed during a disc change cycle. The prior art spindle depress mechanism comprises a bellcrank pivotally mounted and having fingers engaging the depress surface of the spindle. The disc change loader carrier assembly includes a cam member which runs the length of the loader carrier and engages the spindle depress bellcrank for actuation thereof. The cam member comprises a short radius and a flat surface that runs the rest of the length of the loader carrier. As the loader carrier moves in a disc load direction, the spindle depress cam surface engages the bellcrank and rotates it to depress the spindle. The bellcrank rides on the cam surface during the entire disc change cycle.
Contact between the spindle depress bellcrank and the loader carrier spindle depress cam surface during the entire disc change cycle places a frictional "drag" on the loader carrier reducing its efficiency of operation. Furthermore, since the spindle is held down by contact between the bellcrank and the cam surface, the cam surface must be smooth or the spindle will vibrate up and down as the loader carrier moves through the load cycle producing a detrimental effect on the proper loading of the disc. Also, the constant frictional contact between the bellcrank and the cam surface results in wear of the surfaces requiring periodic readjustment of the mechanism to maintain a constant spindle depression height.